Many types of circuit breaker lockout devices are known in the prior art. Some have a locking mechanism on the door of a distribution panel. Others have a locking device for an individual circuit breaker.
Presently, there are O.S.H.A. regulations (Regulations 1910.145 and 1910 Subpart s) which require the presence of a safety padlock alone or a special scissors with a padlock locked thereto for locking out individual circuit breakers when one or more repair or maintenance persons work on the circuit being locked out. The number of circuit breaker lockout devices in the prior art that are designed to be locked out with a padlock alone or with the special scissors and a padlock is very limited.
For example, in U.S. Pat. No. 4,467,152, Gordy discloses a circuit breaker lockout assembly which includes a bent pin arrangement (elements 5 and 6 in FIG. 1 of Gordy). The bent pin arrangement must be inserted into element 10 in two pieces during assembly. The two pieces are then welded together, but the weld is a weak spot in the assembly. The scissors (hasp 7) must be perpendicular to the face of the circuit breaker, as shown in FIG. 3. The combined weight of the hasp 7 and padlock 8 (with up to six padlocks) exert a large amount of torque on the elements 5 and 6 and on the handle of the circuit breaker. Furthermore, this arrangement of the hasp 7 and padlock 8 is very bulky and prevents closure of the door of the distribution panel.
In other prior art, in U.S. Pat. No. 4,897,515, Zubar et al disclose the use of a padlock to lock out distribution panel circuit breakers. The Zubar et al device needs to have precision forming to insure that the mating pieces will match, and any deformation of the two mating pieces renders this device useless. The blocking member of the device (element 16 in FIG. 1 of Zubar et al) can easily be bent out of position allowing undesired operation of the circuit breaker. Furthermore, some of the newer circuit breakers have a shallower shoulder than depicted in the Zubar et al patent (element 28 in FIG. 1), and the device may slip over the shoulder allowing unwanted and hazardous operation of the circuit breaker. Also, a screwdriver or other tool is necessary to install the Zubar et al device.